In the past 20 years, there have developed cooling and heating systems for buildings comprised of a tank or reservoir filled with a phase-changing medium with a plurality of parallel heat exchange circuits submerged in the phase-change medium such as water, and with the parallel heat exchange circuits comprised of tubes which are disposed as coils and coupled to inlet and exhaust manifolds for a brine, refrigerant, or other heat exchange liquid flowing therethrough. Structural elements are employed for supporting the coiled tubes in various arrays with the coils spaced from each other having various tube flows coordinated to minimize the temperature gradient existing throughout the phase-change medium such that ice is formed simultaneously throughout the phase-change medium and with the water about the tubes displaced upwardly to prevent any build up of pressure against the walls of the reservoir.
Representative patents in this art are U.S. Pat. No. 4,294,078 issued Oct. 13, 1981 to Calvin D. MacCracken, assigned to Calmac Manufacturing Corporation; and U.S. Pat. No. 5,109,920 issued May 5, 1992 to Albert E. Merryful and assigned to the common assignee.
U.S. Pat. No. 4,294,078 is characterized by the formation of a preformed flexible roll of tubing and rubberized hair preferably by rolling twin tubings or dual tubes side by side, and spaced slightly from each other into a spiral supported by a mat. First, the ends of the tubes at the outer periphery of the spirals are coupled to respective inlet and outlet manifolds for the brine flow and the ends of the adjacent tubes at the innermost turn of the spirals are connected to each other by way of a reverse bend thereby effecting flow of a brine in different directions throughout the length of the dual tubes from the inlet manifold to the outlet manifold. The adjacent tubes therefore extend longitudinally of the mat in vertically spaced fashion as helical arrays. Such structural content provides parallel flow in adjacent tubes but in opposite flow directions. This results in temperature averaging over the full length of the brine flow within adjacent coils of the heat exchange apparatus.
In U.S. Pat. No, 5,109,920, a plurality of spirals of flexible tubing are disposed one above another with one end of a given spiral being in communication with the inlet manifold and one end of the adjacent spiral being in communication with the outlet manifold and with the opposite ends of each spirals being in communication with each other. Further, the spirals are wound alternately clockwise and counterclockwise, and arranged in pairs one above the other. As such, the end of the radially outer turn of the upper spiral may be connected to the inlet manifold, the end of the radially outer turn of the next adjacent spiral may be connected to the outlet manifold, and the ends of the radially innermost turns of respective adjacent coils may be connected to each other. As such, the brine flows in both coils in the same direction.
Further, the inlet and outlet manifolds preferably extend in vertically upright, side by side fashion, both being adjacent to the outer periphery of the stack of spiral wound coils.
While such heat exchange systems have operated successfully, the refrigerant or brine flow in both coils being in the same direction and while, the heat exchanger of the 920' Patent does enjoy the advantage of the temperature averaging effect in the two immediately adjacent coils as occurs in the 078' Patent, the '920 patent, FIG. 8, has adjacent coils connected in the middle. The disadvantage is that by having two coils in series, tube connections are in the bundle rather than all coils being in parallel and no internal connections, as in this invention.